Golf club head

ABSTRACT

A golf club head comprises a sole portion defined as being surrounded by a sole contour line which is the outer peripheral border of the head in the bottom view of the head. The sole portion is provided with a weight member and a retaining portion retaining the weight member. The weight member comprises a lower surface facing toward a bottom surface side of the head, and a first side surface extending upward from a first side portion of the lower surface. The lower surface is exposed to the outside in a bottom surface of the head. The first side surface is exposed to the outside on the side of the sole contour line.

TECHNICAL FIELD

The present invention relates to a golf club head, and more particularly to a golf club head having a weight member disposed in a sole portion.

BACKGROUND ART

In order to increase the flight distance of a golf ball hit by a golf club, there is a demand for lowering the position of the center of gravity of the golf club head. Lowering the position of the center of gravity brings the sweet spot of the club face closer to the center of the club face (closer to the actual hit position), so the launching angle of the hit ball is increased and the ball spin is reduced. Therefore, lowering the position of the center of gravity of the golf club head results in an increase in the flight distance of the hit ball.

Japanese Patent Application Publication No. 2016-10579 discloses a golf club head comprising a crown portion, a face portion, a sole portion having an opening, and a weight member attached to the opening of the sole portion.

SUMMARY OF THE INVENTION Problems to be Solved by the Invention

In recent years, in addition to the demand for the lowering of the position of the center of gravity, there is a further demand to shift the center of gravity of the head toward a toe side of the head, or a heel side of the head, or a rear side of the head, namely, shift the center of gravity to various positions closer to the outer peripheral of the head (that is, the sole contour line in the bottom view of the head which constitutes the outer peripheral edge of the head in the bottom view of the head).

The conventional golf club head, however, cannot satisfy such demand sufficiently because of the structure, and there is room for improvement.

The present invention was made in view of the above-described problems, and a primary objective of the present invention is to provide a golf club head in which the center of gravity of the head can be shifted toward the sole contour line, while lowering the position of the center of gravity.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

According to the present invention, a golf club head comprises a sole portion defined as being surrounded by a sole contour line which is the outer peripheral border of the head in the bottom view of the head, wherein

the sole portion comprises a weight member and a retaining portion retaining the weight member,

the weight member comprises

a lower surface facing toward a bottom surface side of the head, and a first side surface extending upward from a first side portion of the lower surface, and

the lower surface of the weight member is exposed to the outside in a bottom surface of the head, and

the first side surface of the weight member is exposed to the outside on the side of the sole contour line.

The golf club head may have the following features:

the retaining portion does not protrude toward the sole contour line from the first side surface of the weight member;

in the bottom view of the head, the first side surface of the weight member is located within 5 mm from the sole contour line;

the first side surface of the weight member is exposed to the outside on the rear side of the head;

the first side surface of the weight member is exposed to the outside on a toe side of the head or a heel side of the head;

the weight member comprises two second side surfaces which respectively extend from both ends of the first side surface, getting away from the sole contour line, and the retaining portion comprises a receiving portion which holds the second side surfaces from the side of the sole contour line;

the receiving portion comprises a first receiving surface and a second receiving surface facing each other, wherein the distance between the first receiving surface and the second receiving surface is decreased as approaching the sole contour line;

the first side surface of the weight member faces rearward of the head, and the first receiving surface is located on the toe side of the second receiving surface, wherein the first receiving surface approaches the heel of the head as approaching the rear side of the head, whereas the second receiving surface approaches the toe of the head as approaching the rear side of the head;

the weight member is detachably fixed to the retaining portion;

the weight member is fixed to the retaining portion using a screw;

the sole portion comprises a sole main body and a bulge portion bulged out downwardly therefrom, and the retaining portion is formed in the bulge portion;

the amount of bulging-out of the bulge portion increases toward the sole contour line from a center side of the sole portion.

In the golf club head according to the present invention, the weight member is held by the retaining portion formed in the sole portion, and the lower surface and first side surface of the weight member are exposed to the outside near the sole contour line. Therefore, the weight member can shift the position of the center of gravity of the head toward the sole contour line, namely, to various positions near the sole contour line, while lowering the position of the center of gravity.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a perspective view of a golf club head as an embodiment of the present invention.

FIG. 2 is a perspective view thereof viewed from below.

FIG. 3 is a bottom view thereof.

FIG. 4 is an exploded perspective view of the golf club head shown in FIG. 2.

FIG. 5 is a perspective cross-sectional view taken along line A-A of FIG. 2.

FIG. 6 is a cross-sectional view thereof taken along line A-A of FIG. 2.

FIG. 7 is an enlarged perspective view of the weight member of the golf club head shown in FIG. 2 as an example of the weight member.

FIG. 8A is a bottom view of a golf club head as another embodiment of the present invention.

FIG. 8B is a bottom view of a golf club head as still another embodiment of the present invention.

FIG. 9 is an enlarged cross-sectional view of the retaining portion taken along line B-B of FIG. 3.

FIG. 10 is an enlarged cross-sectional view showing a modification of the retaining portion taken at a position corresponding to the position of line B-B of FIG. 3.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

Embodiments of the present invention will now be described in conjunction with accompanying drawings.

FIGS. 1 to 6 are respectively a front perspective view, a bottom perspective view, a bottom view, an exploded perspective view, a cross-sectional perspective view taken along line A-A in FIG. 2, and a cross-sectional view taken along line A-A in FIG. 2 showing a golf club head 1 (hereinafter, simply referred to as the head 1) as an embodiment of the present invention. In the figures, the head 1 is under its standard state.

In this application including the description and claims, dimensions, positions, directions and the like relating to the club head refer to those under the standard state of the club head unless otherwise noted.

Here, the standard state of a golf club head is such that the club head is set on a horizontal plane HP so that the central axis CL of the golf club shaft (not shown) is inclined at the specified lie angle (not shown) while keeping the central axis CL on a vertical plane VP, and the club face forms the specified loft angle alpha (shown in FIG. 6). Incidentally, in the case of the club head alone, the center line of the shaft inserting hole can be used instead of the central axis of the club shaft.

“Toe-heel direction” of the head is a direction y parallel with the horizontal plane HP and the vertical plane VP.

“Front-back direction” of the head is a direction x parallel with the horizontal plane HP and orthogonal to the vertical plane VP.

“up-down direction” of the head is a direction z orthogonal to the direction x and the direction y.

The head 1 in this embodiment shown in FIGS. 1 to 6 has as a hollow structure with an inner cavity (i) (shown in FIGS. 5 and 6) and is formed in a shape of a typical wood type golf club head in this example.

Here, the wood type golf club means at least a driver (#1), a brushy (#2), a spoon (#3), a buffy (#4), and a creek (#5). Further, the head 1 of the present embodiment may include heads having substantially similar shapes to those of the golf clubs listed above even if the club number or name is different from the golf clubs listed above.

As another embodiment of the present invention, the head 1 may be configured as an iron type golf club head, a utility type golf club head, or a putter type golf club head.

The head 1 in this embodiment is composed of a head main body 10 and a weight member 20.

The head main body 10 in this example comprises a face portion 2, a crown portion 3, and a sole portion 4, defining the inner cavity (i) therein.

The head main body 10 may be made of various metal materials. For example, titanium, titanium alloy, stainless steel, aluminum alloy and the like may be used.

A part of the head main body 10 may be made of nonmetal materials for example fiber reinforced resin and the like.

The front surface of the face portion 2 forms a club face 2 a for hitting a ball. The crown portion 3 extends from the face portion 2 and forms the upper surface of the head. on the heel side of the crown portion 3, the head 1 may be provided with a neck portion 5 as shown in FIGS. 1 and 2. The neck portion 5 is formed in a cylindrical shape having a shaft inserting hole 5 a into which a tip end of a golf club shaft (not shown) inserted and fixed. The center line of the shaft inserting hole 5 a coincides with the central axis CL of the inserted golf club shaft.

The sole portion 4 is defined as a portion surrounded by a sole contour line 6. The sole contour line 6 is the outer peripheral border of the head in the bottom view of the head in the standard state as shown in FIG. 3. The sole contour line 6 does not include the leading edge 2 e of the club face 2 a.

The sole portion 4 comprises a retaining portion 8 and the above-mentioned weight member 20 retained by the retaining portion 8.

The weight member 20 is made of a material having a specific gravity greater than that of the head main body 10. Therefore, the weight member 20 shares its large mass with the sole portion 4 in a concentrated manner, and the position of the center of gravity of the head 1 can be lowered.

For example, a high specific gravity metal material is suitably used for the weight member 20. The type of such metal material is not particularly limited, but an alloy containing tungsten w is preferable. For example, a tungsten-nickel-iron alloy comprising W, Ni and Fe is particularly preferable.

The specific gravity of such alloy can be increased by increasing the proportion of w in its chemical composition. Preferably, the specific gravity of the weight member 20 is set to be not less than 7, more preferably not less than 8, and still more preferably in a range from 10 to 15.

FIG. 7 is an enlarged perspective view of an example of the weight member shown in FIG. 2, wherein the upper side in the figure corresponds to the downside of the head, and the weight member 20 has a lower surface 21 and a first side surface 22. The first side surface 22 extends upward from a first side portion E1 of the lower surface 21.

The weight member 20 in this example has a hexahedral shape as shown in FIGS. 2, 3, and 7.

The lower surface 21 is exposed as a part of the bottom surface of the head. The first side surface 22 is exposed on the sole contour line 6 side of the lower surface 21.

Thus, the weight member 20 can be positioned closer to the sole contour line 6 at a lower position, therefore, the position of the center of gravity of the head 1 can be shifted toward the sole contour line 6 while lowering the position of the center of gravity.

Thus, it is preferable that the weight member 20 is exposed on the rear side of the head as in the present embodiment. For that purpose, it is preferable that the first side surface 22 is exposed as a part of a rear surface 4A of the head 1 which surface extends downwardly from the sole contour line 6 as shown in FIG. 2. Thereby, the center of gravity G of the head 1 can be made deeper from the club face, namely, can be shifted toward backward. As a result, the head 1 can be increased in a lateral moment of inertia around a vertical axis passing through the center of gravity of the head. This helps to improve the directionality of the hit ball.

Further, in the head 1 whose center of gravity G is deep, the tip end portion of the club shaft is bent forward immediately before the impact, and the club face 2 a tends to turn upward at the time of impact, therefore, the launch angle of the hit ball can be increased to increase the flight distance.

In the head 1 in the present embodiment configured as described above, it is possible and preferable that a gravity center height C which is the height from the horizontal plane HP to the center of gravity G of the head as shown in FIG. 6, is not more than 28 mm, more preferably not more than 25 mm, and a gravity center depth D which is the distance in the front-back direction of the head from the leading edge 2 e of the club face 2 a to the center of gravity G of the head, is not less than 37 mm, more preferably not less than 40 mm.

FIG. 8A shown another embodiment of present invention, wherein the first side surface 22 of the weight member 20 is exposed to the outside on the toe side of the head. In this embodiment, the weight member 20 is positioned closer to the sole contour line 6 on the toe side of the head at a lower position, therefore, the position of the center of gravity G of the head can be lowered and shifted toward the toe of the head.

In general, the golf club head tends to have a relatively large weight in the neck portion 5. Therefore, with the above configuration, the distance from the neck portion 5 to the center of gravity G of the head can be increased, and as a result, the lateral moment of inertia of the head can be effectively increased.

FIG. 8B shows another embodiment of present invention, wherein the first side surface 22 of the weight member 20 is exposed to the outside on the heel side of the head. In this embodiment, the weight member 20 is positioned closer to the sole contour line 6 on the heel side of the head at a lower position, therefore, the position of the center of gravity G of the head can be lowered and shifted toward the heel of the head. In such head 1, therefore, since the center of gravity G of the head is shifted toward the heel, the club face easily returns to the address position during downswing, and so-called “ball catch” is improved.

In each of the above described embodiments, in order that the center of gravity G of the head is positioned closer to the sole contour line 6, it is preferred that the first side surface 22 of the weight member 20 is partially, more preferably wholly located within 5 mm from the sole contour line 6 in the bottom view of the head.

In order to show a range within 5 mm from the sole contour line 6, a border line 6 i separated from the sole contour line 6 by 5 mm is shown in FIG. 8A by an alternate long and two short dashes line.

As is clear from FIGS. 3 and 8, the weight member 20 and the retaining portion 8 are provided so as not to protrude from the outer peripheral border of the head even when the head is viewed from above, namely in the top view.

Hereinafter, more detailed description will be made based on the embodiment shown in FIGS. 1-7. But, the following description is applied mutatis mutandis to the embodiments shown in FIGS. 8A and 8B.

As shown in FIG. 7, the weight member 20 in this example is formed in a hexahedral shape as mentioned above.

In addition to the exposed lower surface 21 and first side surface 22, the weight member 20 has

an upper surface 25 on the opposite side of the lower surface 21,

two second side surfaces 23 and 24 respectively extending from both ends of the first side surface 22 in directions away from the sole contour line 6, and

a third side surface 26 on the opposite side of the first side surface 22.

The lower surface 21 and the upper surface 25 preferably have trapezoidal shapes.

In the weight member 20 in this example, the distance F between the two second side surfaces 23 and 24 becomes smaller toward the sole contour line 6.

As shown in FIG. 4, the retaining portion 8 in this example is a portion recessed from the surrounding portion and includes a receiving portion 9 holding the weight member 20.

The receiving portion 9 in this example can support the two second side surfaces 23 and 24 of the weight member 20 from the respective sole contour line 6 sides.

The receiving portion 9 in this example comprises a first receiving surface 11 and a second receiving surface 12 which are formed on the toe side and the heel side, respectively, so as to face to each other.

The space which is formed between the first receiving surface 11 and the second receiving surface 12 to accommodate the weight member 20, is opened on the sole contour line 6 side, and through the opening, the first side surface 22 of the weight member 20 is exposed toward the rear of the head.

The first receiving surface 11 is in contact with the second side surface 23 on the toe side of the weight member 20, and according to the inclination of the second side surface 23, the first receiving surface 11 inclines toward the heel of the head while extending toward the rear of the head.

The second receiving surface 12 is in contact with the second side surface 24 on the heel side of the weight member 20, and according to the inclination of the second side surface 24, the second receiving surface 12 inclines toward the toe of the head while extending toward the rear of the head.

The distance between the first receiving surface 11 and the second receiving surface 12 becomes smaller toward the sole contour line 6 so as to correspond to the distance between the second side surfaces 23 and 23 of the weight member 20.

In the receiving portion 9 configured as described above, an impact force toward the rear of the head which is applied to the weight member 20 when a ball hits the head is received by the first receiving surface 11 and the second receiving surface 12.

In the head 1 in the present embodiment, the first side surface 22 of the weight member 20 is exposed at the back of the head 1, and cannot be supported from the rear of the head. But, owing to the receiving portion 9, the weight member 20 is prevented from moving backward (toward the sole contour line 6), and being displaced rearward from the retaining portion 8.

Preferably, the retaining portion 8 is configured not to protrude toward the sole contour line 6 from the first side surface 22 of the weight member 20 as shown in FIGS. 2 and 6. In other words, the first receiving surface 11 and the second receiving surface 12 terminate without going beyond the first side surface 22 toward the sole contour line 6. Thereby, more weight can be distributed toward the sole contour line 6 of the head 1.

The retaining portion 8 may further comprise a third receiving surface 13 and a fourth receiving surface 14 as shown in FIG. 4.

The third receiving surface 13 is provided so as to contact the third side surface 26 of the weight member 20. Therefore, the third receiving surface 13 can restrict the movement of the weight member 20 in the direction away from the sole contour line 6.

The fourth receiving surface 14 is provided so as to contact the upper surface 25 of the weight member 20. Therefore, the fourth receiving surface 14 can restrict upward movement of the weight member 20.

By forming the third receiving surface 13 and the fourth receiving surface 14, the movement and displacement of the weight member 20 can be more reliably restricted.

As shown in FIGS. 3 and 4, the sole portion 4 preferably includes a sole main body 41 and a bulge portion 42 bulged out downwardly therefrom, and the above-mentioned retaining portion 8 is formed in the bulge portion 42.

The sole main body 41 in this example is configured to have a convex curve which is smoothly curved convexly from the sole contour line 6 toward the center of the sole.

The bulge portion 42 is further bulged out downwardly from a part of the sole main body 41.

By providing the retaining portion 8 on such bulge portion 42, the retaining portion 8 can be positioned more downwardly of the head, therefore, the lower surface 21 of the weight member 20 becomes further close to the horizontal plane HP, and the position of the center of gravity of the head can be further lowered.

Preferably, the bulge portion 42 extends so that the amount of bulging h increases toward the sole contour line 6 from the center side of the sole. In this example, the amount of bulging h increases toward the rear of the head.

Such bulge portion 42 can provide the retaining portion 8 which is capable of holding the weight member 20 at a position lower and closer to the sole contour line 6.

FIG. 9 is a sectional view taken along line B-B in FIG. 3. As shown in FIG. 9 and more clearly shown in FIG. 4, the bulge portion 42 which is provided with the retaining portion 8, is provided with ribs 43 formed on both sides of the weight member 20, namely, on the outer sides of the second side surfaces 23 and 24. Such ribs 43 can increase the bending rigidity of the head main body 10 in a portion surrounding the weight member 20, and can suppress unwanted vibrations of the sole portion 4 at impact.

In order to prevent the weight member 20 from catching on the ground during the swing, the lower surface 21 of the weight member 20 is preferably positioned above or the same level as a curved surface that is smoothly continuous with the lower surfaces 43 a of the ribs 43.

The weight member 20 may be fixed to the retaining portion 8 by various methods.

In order that the user can adjust the center of gravity G of the head by himself/herself by attaching or replacing one by another optimal one among various weight members 20 having different specific gravities, it is preferred that the weight member 20 is detachably fixed to the retaining portion 8.

For example, a screw 30 can be used to detachably fix the weight member 20 to the retaining portion 8. In this case, the weight member 20 is provided with a through hole 27, and the receiving portion 9 is provided with an engaging hole 15.

The screw 30 is penetrated through the through hole 27 from the outer side of the head, and inserted into the engaging hole 15, then screwed by using an appropriate tool (not shown). The screw 30 is engaged with the engaging hole 15 and hold the weight member 20 firmly between the head of the screw and the fourth receiving surface 14 of the retaining portion 8.

If the weight member 20 is fixed to the sole portion 4 by using the screw 30 without the receiving portion 9, the screw 30 is subjected to a large impact force every time the ball is hit, thus the screw 30 becomes liable to be damaged easily.

In the present embodiment, however, by the receiving portion 9, the weight member 20 is also held from the rear side of the head, therefore, the impact applied to the screw 30 is effectively reduced, and the damage of the screw 30 is prevented over a long period.

Here, the screw 30 is not limited to a general screw having a spiral thread groove (in this case, the engaging hole 15 is an internal threaded hole) as long as it can be engaged and disengaged from the engaging hole 15 by a turning operation. For example, a so-called one-touch lock mechanism which can engage and disengage from the engaging hole 15 by turning it by a small angle for example 90 degrees may be included as the screw 30.

FIG. 10 is a cross-sectional view of a modification of the receiving portion 9 taken at a position corresponding to the position of line B-B in FIG. 3.

In this example of the receiving portion 9, the lower surfaces 43 a (the outer surface of the sole portion 4) is provided with a groove 50 (or a step) so as to surround the retaining portion 8, thus surround the weight member 20.

Such groove 50 helps to make the level difference less noticeable and improves the appearance even if the lower surface 21 of the weight member 20 is not completely flush with the lower surfaces 43 a of the retaining portion 8 for example due to unavoidable manufacturing tolerances.

As another example, the weight member 20 can be nondetachably fixed to the retaining portion 8.

While detailed description has been made of preferable embodiments of the present invention, the present invention can be embodied in various forms without being limited to the illustrated embodiments.

DESCRIPTION OF THE REFERENCE SIGNS

-   1 golf club head -   4 sole portion -   6 sole contour line -   8 retaining portion -   9 receiving portion -   10 head main body -   20 weight member -   21 lower surface -   22 first side surface -   23, 24 second side surface -   30 screw -   41 sole main body -   42 bulge portion -   E1 first side portion 

1. A golf club head comprising: a sole portion defined as being surrounded by a sole contour line which is the outer peripheral border of the head in the bottom view of the head, wherein the sole portion comprises a weight member and a retaining portion retaining the weight member, the weight member comprises a lower surface facing toward a bottom surface side of the head, and a first side surface extending upward from a first side portion of the lower surface, the lower surface of the weight member is exposed to the outside in a bottom surface of the head, and the first side surface of the weight member is exposed to the outside on the side of the sole contour line.
 2. The golf club head according to claim 1, wherein the retaining portion does not protrude toward the sole contour line from the first side surface of the weight member.
 3. The golf club head according to claim 1, wherein in the bottom view of the head, the first side surface of the weight member is located within 5 mm from the sole contour line.
 4. The golf club head according to claim 2, wherein in the bottom view of the head, the first side surface of the weight member is located within 5 mm from the sole contour line.
 5. The golf club head according to claim 1, wherein the first side surface of the weight member is exposed to the outside on a rear side of the head.
 6. The golf club head according to claim 3, wherein the first side surface of the weight member is exposed to the outside on a rear side of the head.
 7. The golf club head according to claim 4, wherein the first side surface of the weight member is exposed to the outside on a rear side of the head.
 8. The golf club head according to claim 1, wherein the first side surface of the weight member is exposed to the outside on a toe side of the head or a heel side of the head.
 9. The golf club head according to claim 3, wherein the first side surface of the weight member is exposed to the outside on a toe side of the head or a heel side of the head.
 10. The golf club head according to claim 4, wherein the first side surface of the weight member is exposed to the outside on a toe side of the head or a heel side of the head.
 11. The golf club head according to claim 5, wherein the weight member comprises two second side surfaces which respectively extend from both ends of the first side surface, getting away from the sole contour line, and the retaining portion comprises a receiving portion which holds the second side surfaces from the side of the sole contour line.
 12. The golf club head according to claim 8, wherein the weight member comprises two second side surfaces which respectively extend from both ends of the first side surface, getting away from the sole contour line, and the retaining portion comprises a receiving portion which holds the second side surfaces from the side of the sole contour line.
 13. The golf club head according to claim 11, wherein the receiving portion comprises a first receiving surface and a second receiving surface facing each other, wherein the distance between the first receiving surface and the second receiving surface is decreased as approaching the sole contour line.
 14. The golf club head according to claim 12, wherein the receiving portion comprises a first receiving surface and a second receiving surface facing each other, wherein the distance between the first receiving surface and the second receiving surface is decreased as approaching the sole contour line.
 15. The golf club head according to claim 13, wherein the first side surface of the weight member faces rearward of the head, and the first receiving surface is located on the toe side of the second receiving surface, wherein the first receiving surface approaches the heel of the head as approaching the rear side of the head, whereas the second receiving surface approaches the toe of the head as approaching the rear side of the head.
 16. The golf club head according to claim 14, wherein the first side surface of the weight member faces rearward of the head, and the first receiving surface is located on the toe side of the second receiving surface, wherein the first receiving surface approaches the heel of the head as approaching the rear side of the head, whereas the second receiving surface approaches the toe of the head as approaching the rear side of the head.
 17. The golf club head according to claim 1, wherein the weight member is detachably fixed to the retaining portion.
 18. The golf club head according to claim 17, wherein the weight member is fixed to the retaining portion using a screw.
 19. The golf club head according to claim 1, wherein the sole portion comprises a sole main body and a bulge portion bulged out downwardly therefrom, and the retaining portion is formed in the bulge portion.
 20. The golf club head according to claim 19, wherein the amount of bulging-out of the bulge portion increases toward the sole contour line from a center side of the sole portion. 